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Warning - Flaw in design of A frame verticle support assmbly
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Author:  Macca [ Tue Jan 22, 2008 4:33 am ]
Post subject:  Warning - Flaw in design of A frame verticle support assmbly

Gidday from Western Australia. I bought a 2nd hand Hobie Bravo yesterday, 2 years young and in great condition....or so I thought. We picked her up and took her straight to the beach to go sailing, light winds, a pleasant introduction to sailing for my 7 & 8 year old girls.

After about 20 min of smiles and laughs, my jaw hit the deck when I looked at the mast to see the base swinging about an inch above the ball joint. I scrambled to get the sail in and hold the mast to stop it from tumbling over.

I noticed that the A frame verticle support (forestay) had lifted off the deck of the boat and that the A-support base was still attached. I managed to align the support with the base and guide the mast back down onto the ball then furl the sail. I then jumped in and swam the boat in the 50 metres or so we were off the beach, so thank-ful it was light winds and we were so close to shore.

The break occured at the point the 4 rivets hold the support assembly to the support base. With 4 rivets being used there is precious little cross section left to actually hold the assembley to the deck and an ideal point of corrosion that cannot be seen until it is too late....a very poor design.

I went into my Hobie dealer today, they have seen this before on another boat and actually had stripped the whole mast support assembley off the new boat in their store to fix the customers boat which wasnt very old either. In his case he wasnt able to hold the mast in position and it twisted the whole assembly.

Hopefully someone at hobie knows about this problem and will engineer a solution, as while I have to buy a new vertical support assembley I will start being paranoid about the same thing happening again within a year or so, especially if I am a long way offshore!

Brett
Rockingham
WA

[http://www.flickr.com/photos/23066149@N03/2211294475/]

Author:  mmiller [ Tue Jan 22, 2008 9:54 am ]
Post subject:  Re: Warning - Flaw in design of A frame verticle support ass

Macca wrote:
I bought a 2nd hand Hobie Bravo yesterday, 2 years young and in great condition....or so I thought.


Quote:
Hopefully someone at hobie knows about this problem and will engineer a solution,


Yes, Hobie is aware and has engineered a solution some time ago. This part is now quite solid and does not appear tio be a problem any longer.

Author:  Macca [ Tue Jan 22, 2008 6:42 pm ]
Post subject: 

Thanks Matt, I'd hoped that would be the case. Evidentally they have changed the hex head bolt size as well so I had to take mine in so they could order the right size. I will be interested to see how the assembly has been redesigned to fix this problem. This would also explain why the online part catalogue does not list a part number, it states "Contact us" (hobie).

I will post a photo of the new and old fittings once received so owners know which one they have.

Brett

Author:  Macca [ Thu Jan 24, 2008 1:46 am ]
Post subject: 

Okay, dealer got new vertical support in today (excellent service!). and not too costly at about A$75

The only difference I can see is that it only has two rivets now, increasing the cross sectional area of the internal section securing assembly to the deck. They have also moved the rivets down closer to the end.

This has the effect of bringing the internal hex head bolt further down so it extends about an eighth of an inch further out.

Funnily enough when I fitted the new support it now sits an eighth of an inch above the deck.

Is this right? The (brass?) female fitting in the deck is clear and clean so the hex bolt thread cannot travel any deeper!

Photos on Flikr

http://www.flickr.com/photos/23066149@N03/

Author:  mmiller [ Thu Jan 24, 2008 10:03 am ]
Post subject: 

The intent would be for a flush fit. Perhaps they are drilling the fitting deeper on hulls here now?

Do you also note a new material that the stud is mounted onto? Old had been plastic. New is aluminum.

Two options I guess... trim the bolt / stud to fit flush or leave as is.

Author:  sunjammers [ Thu Jan 24, 2008 2:19 pm ]
Post subject: 

A washer would also work to fill the void.

Author:  Macca [ Thu Jan 24, 2008 6:15 pm ]
Post subject: 

I will look for a nylon washer of that diameter. I dont fancy trying to trim the hex head bolt length.

I hadn't noticed the change it material but upon closer inspection you are right the old fitting was a ballistic type plastic, which I actually thought was ali, the new one as you said is Ali.

Author:  oerterch [ Sat Jan 26, 2008 9:55 am ]
Post subject: 

Macca - Great post and pictures. I also purchased a 2nd hand Bravo, and from the serial number it looks like it was manufactured in 2003. So it kinda freaked me out when your's was only 2 years old and had this problem. I checked my boat and found that my vertical support matched the pictures of the redesigned piece. That's a relief! Also, mine is screwed in flush to the deck.

Matt, is there any way to get a list of components that have been re-engineered over the years to correct structural and/or safety issues? I like to sail in heavy air and wouldn't want to find things out the hard way.

Charlie

Author:  Macca [ Sat Jan 26, 2008 11:39 pm ]
Post subject: 

Charlie, perhaps the previous owner had already replaced it? I was told the boat was 2 years old when I bought it and while it presents as such (in excellent condition) I have no way of knowing if this is the case. It could well have been sitting in the Australian distributors warehouse for a while before being sold. Any way it's water under the bridge (or keel :) ) now. As you pointed out it would be good if Hobie could put this info out there for any mods/updates because of known weakness in design. I guess this forum is a good start, not many companies out there that provide a forum where you can reveal this type of stuff and have the problem acknowledged and advice given.
Imagine if the automobile industry did this sort of thing! I have read through the posts on this list and cant seem to find anything else to keep an eye on.

I had an awesome sail in 20-25 knot winds (gusts to 32 knots) yesterday and was very thankful for the ability to reef the sail :) A friend commented after watching from the beach how much the mast bowed, this boat is certainly a lot of fun and is sailable in almost any conditions..and after that sail I am happy nothing else is likely to bend/break any time soon.

Author:  oerterch [ Sun Jan 27, 2008 12:18 am ]
Post subject: 

Macca, From what I've been told, the last 2 digits in the serial number is the year of manufacture. The serial number is on the hull, right between the 2 mount points (forgot the technical name for them) for the rudder. Its not stamped very deep and is hard to see. What I did was take a piece of paper and placed it over the area. Then rub with a lead pencil. The numbers will show up clearly.

I've been out with the sail reefed to the tell tails and was flying a hull. The Bravo's a blast.

Author:  Macca [ Sun Jan 27, 2008 2:35 am ]
Post subject: 

Okay, number on hull read 04. So I guess if it was made late 04 then sold in 2005 it could be 2-3 years old at best. Even so it has had little use so I am very happy with it. I paid A$3000 including the beach trolley, list price for a new boat and beach trolley here is A$7115.

Author:  cezar [ Thu Aug 27, 2009 11:22 am ]
Post subject:  Re: Warning - Flaw in design of A frame verticle support assmbly

I did all necessary research and replacement.

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